Integral X-ray CT apparatuses and integral X-ray diagnostic apparatuses detect X-rays transmitted through a subject and X-rays scattered by the subject with a plurality of X-ray detection elements included in an X-ray detector. The X-ray detection elements convert the incident X-rays into electric charges, and output the electric charges to a data acquisition system (DAS). Integral X-ray CT apparatuses and integral X-ray diagnostic apparatuses generate a fluoroscopic image, a tomographic image, and a three-dimensional image, and the like, of the subject based on the electric charges collected by the data acquisition system.
The data acquisition system included in the integral X-ray CT apparatus and the integral X-ray diagnostic apparatus acquire an integral value of the energy of the X-rays detected by the X-ray detection elements. Specifically, all the energies of the X-rays detected by the X-ray detection elements are integrated in the integral X-ray CT apparatus and the integral X-ray diagnostic apparatus. For this reason, information of the X-ray having relatively low energy is buried, in the integral X-ray CT apparatus and the integral X-ray diagnostic apparatus. In addition, the energy spectrums of the X-rays for the respective detection circuitry may be shifted from each other due to variations in feedback capacitances of the detection circuitry connected to the X-ray detection elements.
However, the integral X-ray CT apparatus and the integral X-ray diagnostic apparatus cannot specify the energy for each electric charge and correct the energy spectrum of the X-rays for each detection circuitry, because the detection circuitry connected to the X-ray detection elements integrate the electric charges in the feedback capacitance. For this reason, the integral X-ray CT apparatus and the integral X-ray diagnostic apparatus may cause deterioration in image quality due to artifacts caused by beam hardening phenomenon or decrease in contrast resolution in a soft tissue.